Developing Accurate Page Count Time Estimates - Seeking AD Wisdom!

Hey everyone, I'm Diana Ruiz-Perez, an AD currently working on a short film slate for an indie production company. I've done a few shorts and commercials, mostly with a small crew and a V-RAPTOR XL. I'm trying to step up my game in terms of scheduling and really lock in our day plans. One recurring issue I've run into, and something I've heard from more experienced ADs, is how often page counts can be super misleading for estimating scene times.

I'm finding myself almost consistently underestimating complex scenes, even if they're only half a page. For instance, a simple two-shot dialogue scene might fly by, but then a one-eighth page insert shot with a specific practical effect (like a prop splashing water), or even just a character walking down a hallway with specific light cues (we're using a SkyPanel X and some Forza 500 IIs), can suddenly eat up an hour. I've tried breaking down the script into actions and lines, even using a stopwatch during rehearsals, but it still feels like a gamble.

What are some practical methods a new AD can use to develop a more realistic sense of time estimation for different scene types, especially when the written page count doesn't tell the whole story? Any strategies or mental exercises you’ve found invaluable?